There are many kinds of plastic injection molding materials. There are about 100 kinds of plastic materials known all over the world. There are mainly the following categories
Plastics can be classified into thermoplastic and thermosetting plastics according to their plasticity
In general, thermoplastic products can be recycled, while thermosetting plastics cannot
When it is heated to a certain temperature, it will become a viscous substance with certain fluidity and good plasticity， It can be molded into a certain shape under a certain pressure. After cooling, the formed shape can be maintained. If heated again, it can be softened, melted and repeatedly molded.
Thermoplastic materials have the advantages of small specific gravity, good molding performance, excellent electrical conductivity, stable chemical properties, wear resistance, light transmission, easy dyeing and so on. However, there are some shortcomings such as poor mechanical strength and poor manufacturing accuracy. If it is used as engineering plastics, these characteristics should be improved.
The commonly used thermoplastic plastics are polyethylene, polyvinyl chloride, polypropylene, polybutene, isobutylene, ABS, polystyrene, nylon and polyformaldehyde
It has a certain fluidity and plasticity at the initial stage of heating, and it will not become soft even after being heated again, so it is called thermosetting plastics
Thermosetting plastics are characterized by hard texture, good heat resistance and chemical corrosion resistance. Its disadvantage is that the material can not be reused after injection molding.
Common thermosetting plastics are acid formaldehyde resin, urea resin, epoxy resin, unsaturated polyester, silicone resin and trimethyl chloride methanol resin
3：General purpose plastics
It refers to the plastic with large output, wide use and low price. There are eight kinds of plastics, such as polyethylene, polypropylene, phenolic plastics, amino plastics, polyvinyl chloride, polystyrene, polypropylene, ABS, etc
Generally, it refers to the plastics with good mechanical properties, high and low temperature resistance, good dimensional stability and can be used as engineering structure plastics, such as polyamide, polysulfone, etc
In engineering plastics, they are divided into general engineering plastics and special engineering plastics. Engineering plastics can meet higher requirements in mechanical properties, durability, corrosion resistance and heat resistance, and can be processed more conveniently and can replace metal materials
Engineering plastics are widely used in plastic injection mold parts，electronic component, automobile, auto parts，plastic toy，office equipment, machinery, aerospace and other industries. Replacing steel with plastic and wood with plastic has become an international popular trend.. Such as polyamide, polyoxymethylene, polycarbonate, modified polyphenylene oxide, thermoplastic polyester and so on
5：Special (reinforced) plastics
Generally, it refers to the plastics with special functions, which can be used in aviation, aerospace and other special applications. For example, fluoroplastics and organosilicon have outstanding special functions such as high temperature resistance, self lubrication and so on. Reinforced plastics and foam plastics have high strength, high cushioning and other special properties. These plastics belong to the category of special plastics.